William Frederick Happ is scheduled to die by lethal injection at 6 p.m. Tuesday for the 1986 rape and strangulation of a Lauderdale Lakes woman.

The 51-year-old painter formerly of Gilroy, Calif. will be the 80th person executed in Florida since the U.S. Supreme Court reinstated the death penalty in 1976. Happ has spent more time on death row than Angela Crowley, the 21-year-old woman he killed, spent alive.

Happ's only visitors Tuesday were two Catholic spiritual advisers. One, a priest, administered his last rites. He took his final meal at 10 a.m. At his request, Happ had a 12-ounce box of assorted chocolates and 1-1/2 quarts of German chocolate ice cream. His demeanor Tuesday was "calm," a prison spokeswoman said.

Two of Crowley's brothers, two sisters, a nephew and an aunt will gather with journalists to witness the execution at Florida State Prison, located nine miles north of the small northern Florida town of Starke.

Reminiscing about his youngest sister isn't the painful part, Chris Crowley said. Thinking about her brutal end — raped, strangled to death and dumped in a canal — is.

"I've lost quite a few people in my immediate family since that murder and that drives me as much as anything," Chris Crowley said of his resolve to witness Happ's execution. "Knowing that he was sentenced to death and he's still alive, yet I've lost a brother, a sister and a mother since that."

It was May 1986 when "Angie" Crowley's raped and strangled body, wearing only a T-shirt, her sweatpants twisted around her neck, was found by a fisherman on a canal bank in Citrus County.

Delighted with her new job at a travel agency, Crowley, originally from Oregon, Ill., had relocated to Lauderdale Lakes only five months before she was abducted.

She was driving alone to Yakeetown on the Gulf Coast to spend Memorial Day weekend with a former college roommate. At 2 a.m., she pulled off Florida's Turnpike in Wildwood to make a call from a telephone booth at a closed convenience store.

The bubbly, outgoing former high-school cheerleader was never heard from again.

Her Oldsmobile Firenza was found seven blocks from the store.

Three months later, finger-, palm- and footprints found in or near Crowley's car linked Happ to the crime when he was captured in Pittsburgh and booked for a 1984 kidnapping and robbery of a service station in his hometown of Gilroy, Calif.

Happ — who had been arrested in California 30 times between 1974 and 1984 — was convicted of Crowley's murder in the summer of 1989 and sentenced to death.

Happ has outlived Angela Crowley's mother, Julienne, by five years. She died at age 72 in 2008.

"My mother was adamant about the execution and following it through to the end," Chris Crowley, of Newburg, Mo., said. "The murder devastated her. That was one of her last things, 'You stay on top of them and make sure this comes to a conclusion.'"

Joining Chris Crowley to witness the execution will be his 26-year-old son, Bryce Crowley, a practicing attorney born 14 months after Angela Crowley's murder.

"That sort of gives you a perspective as to how long the process has taken," Chris Crowley, 56, said.

Also in attendance will be a sister from Winnebago, Ill., another sister from San Antonio, Texas, a brother from San Diego, Calif., and an aunt from Oregon, Ill.

"I think it's therapeutic for all of us in a way," Chris Crowley, a retired defense contractor, said.

Last month, Happ told a judge he is ready for death and wants no more legal interventions.

"I've thought about this for many years," Happ said at a Sept. 13 court hearing. "I would prefer to have it carried out."

Happ's attorney, Eric Pinkard, of Tampa, said there is unlikely to be any further legal attempts to prevent his client's execution.

"I'm unaware of any intervention, and we're not going to make any," Pinkard said Wednesday. "There's nothing in the works."

Happ will be the first in the state to die by a controversial new lethal-injection cocktail, which will include a sedative — midazolam hydrochloride — that has never been used in an execution.

Midazolam will replace pentobarbital sodium as the unconsciousness-inducing first injection in the three-drug intravenous process.

Florida has altered its drug combination because pentobarbital sodium manufacturers have balked at its use in executions and have prohibited its sale for that purpose. The limited supply the state has on hand will expire at the end of November.

Death-penalty opponents say that if the midazolam fails to work properly, it would make the next two steps in the lethal injection process, paralysis and cardiac arrest, inhumanely painful.

"Hopefully, it's not a disaster," Richard Dieter, executive director of the Death Penalty Information Center in Washington, D.C., said. "That's not how we treat humans, even when they've commited crimes, we don't submit them to medical experiments."